U.S. patent number 10,536,210 [Application Number 15/571,865] was granted by the patent office on 2020-01-14 for interference suppressing method and device in dynamic frequency spectrum access system.
This patent grant is currently assigned to Sony Corporation. The grantee listed for this patent is SONY CORPORATION. Invention is credited to Xin Guo, Chen Sun, Yiteng Wang, Youping Zhao.
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United States Patent |
10,536,210 |
Zhao , et al. |
January 14, 2020 |
Interference suppressing method and device in dynamic frequency
spectrum access system
Abstract
An interference suppressing method and device in a dynamic
frequency spectrum access (DSA) system. The system includes: a
frequency spectrum management device, a primary system including a
plurality of primary devices, and a secondary system including a
plurality of secondary devices. The method includes: transmitting
position information of each of the secondary devices to the
frequency spectrum management device; determining, by the frequency
spectrum management device, a weight factor for a specific
secondary device according to the received position formation; and
performing a second-stage precoding, and in the second-stage
precoding, adjusting, by using the weight factor, an estimated
power of the specific secondary device leaking to the other
secondary device.
Inventors: |
Zhao; Youping (Beijing,
CN), Wang; Yiteng (Beijing, CN), Guo;
Xin (Beijing, CN), Sun; Chen (Beijing,
CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Sony Corporation (Tokyo,
JP)
|
Family
ID: |
57248571 |
Appl.
No.: |
15/571,865 |
Filed: |
April 14, 2016 |
PCT
Filed: |
April 14, 2016 |
PCT No.: |
PCT/CN2016/079275 |
371(c)(1),(2),(4) Date: |
November 06, 2017 |
PCT
Pub. No.: |
WO2016/180150 |
PCT
Pub. Date: |
November 17, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180145741 A1 |
May 24, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
May 13, 2015 [CN] |
|
|
2015 1 0242551 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
16/10 (20130101); H04J 11/0023 (20130101); H04B
17/345 (20150115); H04B 7/086 (20130101); H04W
72/082 (20130101); H04B 7/0617 (20130101); H04W
52/34 (20130101); H04L 27/00 (20130101); H04B
17/354 (20150115); H04L 27/2601 (20130101); H04B
7/0857 (20130101); H04W 72/10 (20130101); H04W
16/14 (20130101) |
Current International
Class: |
H04B
7/08 (20060101); H04B 17/354 (20150101); H04W
16/10 (20090101); H04W 72/10 (20090101); H04W
72/08 (20090101); H04W 16/14 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
102812646 |
|
Dec 2012 |
|
CN |
|
103442366 |
|
Dec 2013 |
|
CN |
|
103780356 |
|
May 2014 |
|
CN |
|
104144482 |
|
Nov 2014 |
|
CN |
|
2014/180260 |
|
Nov 2014 |
|
WO |
|
Other References
Xin Xia et al: 11SINR or SLNR: In Successive User Scheduling in
MU-MIMO Broadcast Channel with Finite Rate Feedback 11,
Communications and Mobile Computing (CMC), 2010 International
Conference on, IEEE, Piscataway, NJ, USA, Apr. 12, 2010 (Apr. 12,
2010), pp. 383-387, XP031680329, ISBN: 978-1-4244-6327-5. cited by
applicant .
Chen Sun (Sony): "Coexistence Management Considering Pre-coding and
Priority;
19-15-0093-00-001a-coexistence-management-considering-pre-codin-
g-and-priority", IEEE Draft;
19-15-0093-00-001A-Coexistence-Management-Considering-Pre-Coding-And-Prio-
rity, IEEE-SA Mentor, Piscataway, NJ USA,VO I . 802 .19 .1,Nov. 9,
2015 (Nov. 9, 2015), pp. 1-11, XP068099767. cited by applicant
.
Supplemental European Search Report dated Oct. 16, 2018, issued in
corresponding European Application No. 16792000. cited by applicant
.
International Search Report dated Jul. 5, 2016 in PCT/CN2016/079275
filed Apr. 14, 2016. cited by applicant.
|
Primary Examiner: Vlahos; Sophia
Attorney, Agent or Firm: Xsensus LLP
Claims
The invention claimed is:
1. A spectrum management device, comprising one or more processors
configured to: get position information of each secondary device in
a secondary system including a plurality of secondary devices; and
determine a weighting factor for a specific secondary device based
on the position information, wherein the weighting factor is used
to describe estimation of power leaked from the specific secondary
device to other secondary devices, wherein the one or more
processors are further configured to: determine whether the
specific secondary device is capable of performing first-stage
precoding, and determine a transmission power for the specific
secondary device based on a result of the determination, and
wherein a higher transmission power is determined for the specific
secondary device in a case where the specific secondary device is
capable of performing the first-stage precoding than in a case
where the specific secondary device is not capable of performing
the first-stage precoding.
2. The spectrum management device according to claim 1, wherein the
one or more processors are further configured to: determine a
priority for each of the secondary devices; determine the number of
the priorities of all active secondary devices on the same
frequency band as the specific secondary device within a
predetermined range of the specific secondary device, and
preliminarily determine a value of the weighting factor based on
the number of the priorities; and adjust the preliminarily
determined value based on the number or a distribution density of
the active secondary devices on the same frequency band as the
specific secondary device which have the same priority as the
specific secondary device, to determine the weighting factor.
3. The spectrum management device according to claim 2, wherein the
one or more processors are further configured to increase the
preliminarily determined value in a case where the number or the
distribution density of the active secondary devices on the same
frequency band as the specific secondary device which have the same
priority as the specific secondary device exceeds a predetermined
threshold.
4. The spectrum management device according to claim 1, wherein the
one or more processors are further configured to determine, using a
channel information database, a first interference channel
information from the specific secondary device to a specific
primary device in a primary system and a second interference
channel information from the specific secondary device to other
secondary devices, based on the position information and the
determined transmission power of the specific secondary device.
5. The spectrum management device according to claim 1, wherein the
one or more processors are further configured to determine
position-related information and/or device capability information
of a specific primary device in a primary system, and
position-related information and/or device capability information
of other secondary devices, based on the position information and
the determined transmission power of the specific secondary
device.
6. A secondary device in a secondary system, comprising one or more
processors configured to: determine position information of the
secondary device so that a spectrum management device determines a
weighting factor for the secondary device based on the position
information, wherein it is determined whether the secondary device
is capable of performing first-stage precoding, a transmission
power for the secondary device is determined based on a result of
the determination, and a higher transmission power is determined
for the secondary device in a case where the secondary device is
capable of performing the first-stage precoding than in a case
where the specific secondary device is not capable of performing
the first-stage precoding, the one or more processors further
configured to obtain the determined transmission power; wherein the
one or more processors are further configured to perform
second-stage precoding in which the weighting factor determined by
the spectrum management device is used to adjust estimation of
power leaked from the secondary device to other secondary devices;
and wherein the one or more processors are further configured to
perform the first-stage precoding before performing the
second-stage precoding in the case where the secondary device is
capable of performing the first-stage precoding.
7. The secondary device according to claim 6, wherein the one or
more processors are further configured to: perform the first-stage
precoding using a first interference channel information from the
secondary device to a specific primary device in a primary system;
and perform the second-stage precoding using a second interference
channel information from the secondary device to other secondary
devices in the secondary system.
8. The secondary device according to claim 7, wherein the one or
more processors are further configured to: determine the first
interference channel information based on position-related
information and/or device capability information of the specific
primary device determined by the spectrum management device; and
determine the second interference channel information based on
position-related information and/or device capability information
of the other secondary devices determined by the spectrum
management device.
9. The secondary device according to claim 7, wherein the one or
more processors are further configured to: determine device
capability information of the specific primary device using
position-related information of the specific primary device
determined by the spectrum management device, to perform channel
measurement, so as to determine the first interference channel
information; and determine device capability information of the
other secondary devices using position-related information of the
other secondary devices determined by the spectrum management
device, to perform channel measurement, so as to determine the
second interference channel information.
10. The secondary device according to claim 8, wherein the device
capability information comprises an antenna array type, an antenna
boresight azimuth angle and an antenna boresight elevation
angle.
11. The secondary device according to claim 8, wherein the
position-related information of the specific primary device is
position information of a reference point, and the reference point
is a position within a coverage area of the primary system which is
closest to the secondary device.
12. The secondary device according to claim 7, wherein the one or
more processors are further configured to demodulate a received
signal using the weighting factor, the first interference channel
information and the second interference channel information.
13. A method for suppressing interference in a communication
system, the method comprising: transmitting position information of
each of secondary devices to a spectrum management device;
determining, by the spectrum management device, a weighting factor
for a specific secondary device based on the received position
information; performing second-stage precoding in which the
weighting factor is used to adjust estimation of power leaked from
the specific secondary device to other secondary devices;
determining whether the specific secondary device is capable of
performing first-stage precoding; and determining a transmission
power for the specific secondary device based on a result of the
determination, wherein a higher transmission power is determined
for the specific secondary device in a case where the specific
secondary device is capable of performing the first-stage precoding
than in a case where the specific secondary device is not capable
of performing the first-stage precoding.
14. The method according to claim 13, further comprising:
transmitting a priority of each of the secondary devices to the
spectrum management device; and determining, by the spectrum
management device, the weighting factor for the specific secondary
device based on the received priorities.
15. The method according to claim 14, further comprising:
determining the number of the priorities of all active secondary
devices on the same frequency band as the specific secondary device
within a predetermined range of the specific secondary device, and
preliminarily determining a value of the weighting factor based on
the number of the priorities; and adjusting the preliminarily
determined value based on the number or a distribution density of
the active secondary devices on the same frequency band as the
specific secondary device which have the same priority as the
specific secondary device, to determine the weighting factor.
16. The method according to claim 13, further comprising: in the
case where the secondary device is capable of performing the first
stage precoding, performing first-stage precoding before performing
the second-stage precoding.
17. The method according to claim 16, further comprising:
determining, by the spectrum management device using a channel
information database, a first interference channel information from
the specific secondary device to a specific primary device in a
primary system and a second interference channel information from
the specific secondary device to other secondary devices based on
the position information and the determined transmission power of
the specific secondary device, and transmitting, by the spectrum
management device, the first interference channel information and
the second interference channel information to the specific
secondary device.
Description
TECHNICAL FIELD
The present disclosure relates to interference suppressing method
and device in a dynamic frequency spectrum access system, and in
particular to interference suppressing method and device in a
dynamic frequency spectrum access system which is capable of
distinguishing priorities of secondary devices.
BACKGROUND
With the rapid development of information technology and
multi-service wireless network, there is an increasing demand for
broadband wireless services. Frequency spectrum, as a precious
non-renewable resource, is gradually becoming short. However, the
conventional fixed frequency spectrum allocation strategy results
in that a lot of frequency spectrum allocated to authorized users
are not be used in certain time periods. Therefore, the spectrum
utilization ratio is low, and a large amount of frequency spectrum
is wasted. With the emergence of cognitive radio (CR) technology,
the spectrum utilization ratio is improved, and the problem caused
by insufficient spectrum resource is mitigated. Therefore, the
cognitive radio technology becomes a research hotspot in the field
of wireless communication.
A device (referred to as "a secondary device" herein) using the
cognitive radio technology may opportunistically access to a legal
frequency band of an authorized user equipment (referred to as "a
primary device" herein) without affecting normal communication of
the authorized user equipment. As such, dynamic spectrum access
(DSA) is implemented, and the spectrum utilization ratio is
improved.
The introduction of the cognitive radio technology can ameliorate
the problem of insufficient spectrum resource. However, since
different modulated signals are transmitted on the same frequency
band, a primary device which operates on the same frequency band as
a secondary device may be interfered by the signal transmitted from
the secondary device. Therefore, an advanced algorithm is required
to control the operating frequency and the transmission power of
the secondary device, to ensure the communication quality of the
primary device. In addition, the secondary devices operating on the
same frequency band may interfere with each other. Thus the
interference between the secondary devices should also be taken
into consideration.
For a DSA system in which the secondary devices have different
priorities (or QoS levels), it is required to design an
interference suppressing method which may take the priorities of
the secondary devices into consideration and guarantee different
QoS for the secondary devices having different priorities, while
the priorities of the secondary devices are not taken into
consideration in currently existing interference suppressing
methods.
SUMMARY
To solve the above problems, new interference suppressing method
and device applicable to the DSA system are provided in the present
disclosure.
In an aspect of the present disclosure, a spectrum management
device is provided, which includes one or more processors
configured to: determine position information of each secondary
device in a secondary system comprising multiple secondary devices;
and determine a weighting factor for a specific secondary device
based on the position information, wherein the weighting factor is
used to adjust estimation of power leaked from the specific
secondary device to other secondary devices.
In another aspect of the present disclosure, a secondary device in
a secondary system is provided. The secondary device includes one
or more processors configured to: determine position information of
the secondary device, so that a spectrum management device
determines a weighting factor for the secondary device based on the
position information.
In another aspect of the present disclosure, a method for
suppressing interference in a communication system is provided. The
communication system includes a spectrum management device, a
primary system including multiple primary devices, and a secondary
system including multiple secondary devices. The method includes:
transmitting position information of each of the secondary devices
to the spectrum management device; determining, by the spectrum
management device, a weighting factor for a specific secondary
device based on the received position information; and performing
second-stage precoding, in which the weighting factor is used to
adjust estimation of power leaked from the specific secondary
device to other secondary devices.
According to the technology of the present disclosure, transmission
precoding is performed on the secondary device in consideration of
the priority of the secondary device, thereby guaranteeing
different qualities of service (QoS) for the secondary devices
having different priorities. In addition, on the premise of
ensuring that interference from the secondary device to a primary
device is lower than a certain threshold, a limitation on the
maximum transmission power for the secondary device is relaxed with
the technology according to the present disclosure, compared with
the conventional power control method. The present disclosure is
applicable to a DSA system in which priorities of secondary devices
are distinguished, thereby achieving a goal of joint optimization
for QoS of the primary device and the secondary device.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure may be better understood with reference to
the description given hereinafter in conjunction with the drawings,
in which same or similar reference numerals are used to represent
the same or similar components throughout the drawings. The
drawings together with the following detailed description are
included in this specification and form a part of this
specification, and are intended to further illustrate the preferred
embodiments of the present disclosure and to explain the principles
and advantages of the present disclosure. In the drawings:
FIG. 1 is a schematic diagram showing architecture of a DSA
system;
FIG. 2 is a schematic flowchart for determining an interference
leakage weighting factor;
FIG. 3 is a schematic flowchart for determining a transmission
power of a secondary device;
FIG. 4A is a schematic flowchart of a first example for determining
interference channel information from a secondary device to a
primary device;
FIG. 4B is a schematic flowchart of a second example for
determining interference channel information from a secondary
device to a primary device;
FIG. 4C is a schematic flowchart of a third example for determining
interference channel information from a secondary device to a
primary device;
FIG. 5A is a schematic flowchart of a first example for determining
interference channel information from a specific secondary device
to other secondary device;
FIG. 5B is a schematic flowchart of a second example for
determining interference channel information from a specific
secondary device to other secondary device;
FIG. 5C is a schematic flowchart of a third example for determining
interference channel information from a specific secondary device
to other secondary device;
FIG. 6 is a schematic flowchart of communication between a
secondary device as a transmitting terminal and a secondary device
as a receiving terminal;
FIG. 7 is a flowchart showing two-stage transmission precoding and
a demodulation algorithm of a secondary device;
FIG. 8 is a structural block diagram of a secondary device
according to the present disclosure;
FIG. 9 is a structural block diagram of a spectrum coordinator
according to the present disclosure; and
FIG. 10 is a block diagram showing an exemplary configuration of
computer hardware.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIG. 1 is a schematic diagram showing architecture of a
multi-antenna DSA system. An upper dashed box in FIG. 1 represents
a primary system. The primary system includes multiple primary base
stations N.sub.T-P, and multiple primary devices PU.sub.1 to
PU.sub.m communicating in legally-allocated frequency bands. Each
primary device adopts multi-antenna configuration, G.sub.j
represents a channel matrix of the primary system, and n.sub.p1 to
n.sub.pm represent additive white gaussian noise on communication
channels of the multiple primary devices, respectively.
A lower dashed box in FIG. 1 represents a secondary system. The
secondary system includes multiple secondary base stations
N.sub.T-S, and multiple secondary devices SU.sub.1 to SU.sub.k
using cognitive radio technology. As described above, on the
premise of ensuring communication quality of the primary device,
one or more of the secondary devices SU.sub.1 to SU.sub.k may
opportunistically access to the legal frequency band of the primary
device, thereby achieving dynamic spectrum access and improving the
spectrum utilization ratio. Each of the secondary devices has
multi-antenna configuration, H.sub.ri represents a channel matrix
of the secondary system, and n.sub.s1 to n.sub.sk represent
additive white gaussian noise on communication channels of the
multiple secondary devices, respectively.
P.sub.ij between the upper dashed box and the lower dashed box
represents a channel matrix between a j-th primary device as a
transmitting terminal and an i-th secondary device as a receiving
terminal, and is used for characterizing interference from the
primary device to the secondary device. Q.sub.ij represents a
channel matrix between an i-th secondary device as a transmitting
terminal and a j-th primary device as a receiving terminal, and is
used for characterizing interference from the secondary device to
the primary device.
As described above, different secondary devices have different
priorities, that is, different QoS levels. An interference leakage
weighting factor is proposed under consideration of the priorities
of the secondary devices in the present disclosure. The
interference leakage weighting factor is used to weight a power
(that is, interference) which is leaked from a specific secondary
device to other secondary device, thereby guaranteeing different
QoS based on different priorities of the secondary devices.
Specifically, for the secondary device having a higher priority, a
smaller value of an interference leakage weighting factor is set,
on the contrary, for the second device having a lower priority, a
larger value of an interference leakage weighting factor is set. In
this way, a value obtained by multiplying a smaller value of the
interference leakage weighting factor by a power leaked from a
specific secondary device to other secondary device is smaller,
which indicates that the power leaked from the specific secondary
device to other secondary device may be estimated to be lower, that
is, an interference from the specific secondary device to other
secondary devices may be estimated to be low. Hence, interference
from the secondary device having the higher priority to other
secondary devices may be estimated to be lower. Accordingly, when
performing transmission precoding, interference from the secondary
device having the higher priority to other secondary devices may be
considered to be less than the interference from a secondary device
having a lower priority on other secondary device, thereby
providing better QoS guarantee to the secondary device having the
higher priority than the secondary device having the lower
priority.
FIG. 2 is a schematic flow for determining an interference leakage
weighting factor. As shown in FIG. 2, a secondary device 100
reports position information thereof to a spectrum coordinator (SC)
in step S210. Optionally, the secondary device 100 may report a
priority thereof to the SC in a case where the SC does not know the
priority of the secondary device 100. Then, the SC determines an
interference leakage weighting factor .alpha. for the secondary
device 100 based on the received information in step S220, a value
of .alpha. is set dynamically based on the number of priorities of
all active (operative) secondary devices on the same frequency band
as the secondary device 100 within a predetermined range of the
secondary device 100 and the number and a distribution density of
the secondary devices having the same priority as the secondary
device 100, in this way, a system resource can be avoided from
being wasted effectively. Step S220 will be described in detail
hereinafter. Then, the SC transmits the determined .alpha. to the
secondary device 100 in step S230.
Additionally and optionally, the secondary device 100 may also
report payment information of a user to the SC in step S210. The SC
may determine a small interference leakage weighting factor .alpha.
for the secondary device 100 in a case where the user pays a
fee.
Step S220 performed by the SC will be described in detail as
follows.
When determining the interference leakage weighting factor .alpha.
for the secondary device 100, the SC firstly determines an
influence range (that is, a range, a device in which may suffer
from interference of the secondary device 100) of the secondary
device 100 for example based on information such as the positional
information, an operating frequency and a transmission power of the
secondary device 100, and then determines the number of priorities
of all active secondary devices on the same frequency band as the
secondary device 100 within the influence range. It should be noted
that, for example, an operating frequency of the secondary device
may be known by the SC in advance, and the transmission power of
the secondary device may be determined by the SC. For example, it
is assumed that the secondary system includes secondary devices
having four priorities (priority 1 to priority 4), and there are
only active secondary devices on the same frequency band as the
secondary device 100 which have three priorities within the
influence range of the secondary device 100 (assumed that there is
no secondary device having the priority 2). In this case, it can
determine that the number of priorities of all active secondary
devices on the same frequency band as the secondary device 100
within the influence range of the secondary device 100 is 3. Then,
the priorities of all active secondary devices on the same
frequency band as the secondary device 100 within the influence
range are re-classified into new priority 1 to new priority 3. For
example, since there is no secondary device having the original
priority 2, the secondary device having the original priority 3 can
be classified as the new priority 2, and so on. Then, three values
of .alpha. are evenly set within a range from 0 to 1, inclusively,
for example, 0, 0.5 and 1, and the three values correspond to new
three priorities respectively. In the example, assumed that the
original priority of the secondary device 100 is 3, the priority of
the secondary device 100 is changed to be 2 after
re-classification, a value of an interference leakage weighting
factor .alpha. for the secondary device 100 is preliminarily
determined to be 0.5.
After the above preliminary determination, a value "0.5" of .alpha.
is adjusted based on the number and a distribution density of
active secondary devices on the same frequency band as the
secondary device 100 which have the same priority (priority 2) as
the secondary device 100, to determine a final interference leakage
weighting factor .alpha.. Specifically, in a case where there is a
large number of the active secondary devices on the same frequency
band as the secondary device 100 or the active secondary devices on
the same frequency band as the secondary device 100 are distributed
densely, in order to suppress mutual interference between the
secondary devices having the same priority and guarantee QoS of
each of the secondary devices, interference from each of the
secondary devices is considered to be larger, hence, the value
"0.5" of .alpha. preliminarily determined is increased.
Those skilled in the art readily design various adjustment schemes
according to design requirements or practical applications. For
example, the numbers of the secondary devices having the same
priority may be classified into multiple ranges, a corresponding
adjustment amount is set for each range, and the adjustment amount
is not limited to increment but may also be decrement. The
preliminarily determined value of .alpha. may be adjusted based on
a preset adjustment amount in a case where the number of the active
secondary devices having the same priority as the secondary device
100 falls within a certain range.
FIG. 3 is a schematic flow for determining a transmission power of
the secondary device 100. As shown in FIG. 3, the secondary device
100 reports information indicating whether the secondary device 100
can perform subspace mapping (SP) precoding to the spectrum
coordinator SC in step S310. SP precoding may project the
transmitted signal of the secondary device into a zero space of an
interference channel from the secondary device to a primary device
according to a matrix subspace projection theory, thereby
effectively suppressing interference to the primary device which is
caused by the secondary device occupying the spectrum of the
primary device.
Then, the SC determines a transmission power of the secondary
device 100 based on the received information in step S320.
Specifically, the SC determines a transmission power of the
secondary device 100 with a conventional power control method in a
case where the information indicates that the secondary device 100
cannot perform SP precoding. Interference from the secondary device
100 to the primary device can be suppressed to a certain extent in
a case where the information indicates that the secondary device
100 can perform SP precoding. In this case, the limitation on the
transmission power of the secondary device 100 may be appropriately
relaxed. Hence, the SC may appropriately increase the transmission
power of the secondary device 100 (compared with conventional power
control), preferably, the transmission power of the secondary
device 100 may be increased by 26 dB in maximum. Then the SC
notifies the secondary device 100 of the determined transmission
power in step S330.
FIGS. 4A to 4C show flowcharts of three examples for determining
interference channel information from the secondary device to the
primary device.
As shown in FIG. 4A, the secondary device 100 reports the position
information and a device descriptor thereof to the SC in step S411.
The SC may obtain physical configuration for example a maximum
transmission power of the secondary device 100, based on the device
descriptor.
Then, in step S412, the SC determines an influence range of the
secondary device 100 (that is, a range, a device in which suffer
from interference from the secondary device 100) based on
information such as the position, an operating frequency and the
transmission power of the secondary device 100, and then detects
positions and operating frequencies of one or more primary devices
within the influence range, to determine the primary device
(referred to as "interfered primary device" hereinafter) which is
most susceptible to interference from the secondary device 100, and
the SC determines interference channel information from the
secondary device 100 to the interfered primary device using an
advanced geolocation engine (AGE) database.
The SC transmits the determined interference channel information
from the secondary device 100 to the interfered primary device to
the secondary device 100 in step S413.
FIG. 4B shows another example for determining interference channel
information from the secondary device to the primary device. In the
example, assumed that a spectrum coordinator SC knows device
capability information on each of the primary devices in the
primary system. For example, the primary device may actively report
the device capability information, or the SC may query the primary
device about the device capability information.
The device capability information may include, for example: antenna
array type, such as a linear array, a planar array and a circular
array; antenna boresight azimuth angle representing an angle from
north end of the longitudinal axis to an antenna in clockwise
direction, and a value thereof is a real number; and antenna
boresight elevation angle representing an elevation angle of an
antenna from a direction parallel to the ground to a direction
perpendicular to the sky, and a value thereof is a real number.
As shown in FIG. 4B, the secondary device 100 reports the position
information and a device descriptor thereof to the SC in step S421.
As described above, the device descriptor may include information
on the maximum transmission power of the secondary device 100.
Then, in step S422, the SC determines an influence range of the
secondary device 100 based on information such as position,
operating frequency and transmission power of the secondary device
100, and detects position and operating frequency of one or more
primary devices within the influence range, so as to determine the
interfered primary device which is most susceptible to interference
from the secondary device 100.
The SC transmits position information or other parameter
information (referred to as "position-related information"
hereinafter) for characterizing a relative position and the device
capability information of the interfered primary device to the
secondary device 100 in step S423. It should be noted that, the SC
may use position information of a reference point as the position
information of the interfered primary device in a case where the SC
does not know the position information of the interfered primary
device. The reference point is a position point in a coverage area
of the primary system which is closest to the secondary device
100.
The secondary device 100 calculates interference channel
information from the secondary device 100 to the interfered primary
device based on the received position information and the device
capability information of the interfered primary device in step
S424.
FIG. 4C shows another example for determining interference channel
information between the secondary device and the primary
device.
As shown in FIG. 4C, the secondary device 100 reports the position
information and a device descriptor thereof to a SC in step S431.
As described above, the SC may obtain a maximum transmission power
of the secondary device 100 based on the device descriptor.
In step S432, the SC determines an influence range of the secondary
device 100 based on, for example, the position, an operating
frequency and the transmission power of the secondary device 100,
and detects positions and operating frequencies of one or more
primary devices within the influence range, so as to determine the
interfered primary device which is most susceptible to interference
from the secondary device 100. The SC transmits the determined
position information of the interfered primary device to the
secondary device 100 in step S433.
In step S434, the secondary device 100 performs information
interaction and actual channel measurement with the interfered
primary device based on the received position information of the
interfered primary device, to obtain interference channel
information between the secondary device 100 and the interfered
primary device. For example, in order to perform channel
measurement, the secondary device 100 and the interfered primary
device should exchange device capability information with each
other. The device capability information may be exchanged under
control of the SC, or may be exchanged by the secondary device 100
and the interfered primary device via a wired or wireless link.
FIGS. 5A to 5C are flowcharts of three examples for determining
interference channel information from a specific secondary device
to other secondary device.
As shown in FIG. 5A, the secondary device 100 reports position
information and a device descriptor thereof to the SC in step S511.
The SC may obtain physical configuration for example a maximum
transmission power of the secondary device 100 based on the device
descriptor.
In step S512, the SC determines an influence range (that is, a
range, a device in which suffers from interference from the
secondary device 100) of the secondary device 100 based on, for
example, the position, an operating frequency and a transmission
power of the secondary device 100, detects positions and operating
frequencies of one or more other secondary devices within the
influence range, to determine other secondary device which suffer
from interference from the secondary device 100, and the SC
determines interference channel information from the secondary
device 100 to other secondary device using an AGE database.
Then, the SC transmits the determined interference channel
information from the secondary device 100 to other secondary device
to the secondary device 100 in step S513.
FIG. 5B shows another example for determining interference channel
information between the secondary devices. In the example, each of
the secondary devices in the secondary system reports device
capability information thereof to the spectrum coordinator SC
regularly.
As shown in FIG. 5B, the secondary device 100 reports position
information and a device descriptor thereof to the SC in step S521.
As descried above, the device descriptor may include information on
a maximum transmission power of the secondary device 100.
In step S522, the SC determines an influence range of the secondary
device 100 based on, for example, the position, an operating
frequency and a transmission power of the secondary device 100, and
detects positions and operating frequencies of one or more other
secondary devices within the influence range, to determine other
secondary device which suffer from interference from the secondary
device 100.
Then the SC transmits position information (or other parameter
information for characterizing a relative position) and device
capability information of the determined interfered other secondary
device to the secondary device 100 in step S523.
The secondary device 100 calculates interference channel
information from the secondary device 100 to the interfered
secondary device based on the received position information and the
received device capability information of the interfered secondary
device in step S524.
FIG. 5C shows another example for determining interference channel
information between the secondary devices.
As shown in FIG. 5C, the secondary device 100 reports position
information and a device descriptor thereof to the SC in step
S531.
Then, in step S532, the SC determines an influence range of the
secondary device 100 based on, for example, the position, an
operating frequency, a transmission power of the secondary device
100, and determines other secondary devices on the same frequency
band as the secondary device 100 which suffer from interference
within the influence range.
Then, the SC transmits position information of the determined
interfered other secondary device to the secondary device 100 in
step S533.
In step S534, the secondary device 100 performs information
interaction and actual channel measurement with the interfered
secondary device based on the received position information of the
interfered secondary device, to obtain interference channel
information from the secondary device 100 and the interfered
secondary device. For example, in order to perform channel
measurement, the secondary device 100 and the interfered secondary
device need to exchange device capability information with each
other. The device capability information may be exchanged under
control of the SC, or may be exchanged by the secondary device 100
and the interfered secondary device via a wired or wireless
link.
FIG. 6 is a flowchart showing communication between secondary
devices, and the flow includes two-stage precoding at a
transmitting terminal and demodulation processing at a receiving
terminal.
As shown in FIG. 6, in step S610, a secondary device 600 as the
transmitting terminal performs first-stage precoding, that is, SP
precoding, to suppress interference from the secondary device 600
to a primary device on the same frequency band as the secondary
device 600. In the first-stage precoding, the above-described
interference channel information from the secondary device 600 to
the interfered primary device is used.
Next, the secondary device 600 performs second-stage precoding in
step S620, to suppress interference from the secondary device 600
to other secondary devices on the same frequency band as the
secondary device 600. In the second-stage precoding, the
above-described interference channel information from the secondary
device 600 to other secondary device is used.
The second-stage precoding is an improvement in the present
disclosure for a conventional signal to leakage and noise ratio
(SLNR) algorithm. A focus for the improvement is to take a case
that different secondary devices have different priorities into
consideration, and an interference leakage weighting factor .alpha.
related to the priority is introduced. The second-stage precoding
according to the present disclosure can guarantee a higher QoS for
a secondary device having a higher priority. The second-stage
precoding will be described in detail hereinafter.
Then, the secondary device 600 as the transmitting terminal
transmits an interference leakage weighting factor .alpha.,
interference channel information from the secondary device 600 to
the interfered primary device, and interference channel information
from the secondary device 600 to other interfered secondary device
used in precoding to a secondary device 700 as a receiving terminal
in step S630. Optionally, for example, in examples shown in FIGS.
4A and 5A, the SC rather than the secondary device 600 as the
transmitting terminal directly transmits the above information to
the secondary device 700 at the receiving terminal.
Further, the secondary device 600 as the transmitting terminal
transmits data to the secondary device 700 as the receiving
terminal in step S640. It is noted that, although FIG. 6
illustrates the above information and the above data are
transmitted in two steps, the present disclosure is not limited
thereto. For example, the above information and the above data may
be transmitted in the same step or in a different order.
In step S650, the secondary device 700 as the receiving terminal
demodulates the received data based on the received interference
channel information and the received interference leakage weighting
factor and according to the minimum mean square error (MMSE)
criterion.
FIG. 6 is a schematic flow of a general communication flow, and
various modifications may also be made on the above flow according
to actual conditions.
For example, in a case where no primary device operates in the
primary system, SP precoding in step S610 may be omitted, hence,
the secondary device 600 as the transmitting terminal only performs
the second-stage precoding in step S620. Correspondingly,
processing for acquiring the interference channel information
between the secondary device and the interfered primary device as
in FIGS. 4A to 4C may also be omitted.
For example, in a case where the present disclosure is applied to a
DSA system in which the secondary devices have the same priority,
and since it is no required to consider priorities of the secondary
devices, the same interference leakage weighting factors .alpha.
may be determined for the secondary devices in the second-stage
precoding. For example, a value of .alpha. may be set to be 1. In
this case, the second-stage precoding is the same as the
conventional SLNR algorithm.
FIG. 7 is a flowchart showing algorithms of precoding at a
secondary device as the transmitting terminal and demodulation at a
secondary device as the receiving terminal.
As shown in FIG. 7, in step S710, for an i-th secondary device as a
transmitting terminal, a primary device which is most susceptible
to interference from the i-th secondary device is determined, and
interference channel information from the i-th secondary device to
the interfered primary device is further determined. Then, a
first-stage precoding matrix F.sub.i.sup.(1) is obtained based on
the determined interference channel information according to the
following equation (1), to perform first-stage precoding.
F.sub.i.sup.(1)=V.sub.0.sup.(0) (1)
where V.sub.0.sup.(0) represents a zero space of a normalized
interference channel matrix from the i-th secondary device to the
interfered primary device.
In particular, the first-stage precoding matrix F.sub.i.sup.(1) may
be set as a unit matrix in a case where no primary device
operates.
In step S720, for the i-th secondary device as the transmitting
terminal, a second-stage precoding matrix F.sub.i.sup.(2) is
determined to perform second-stage precoding.
As described above, the second-stage precoding according to the
present disclosure is an improvement for a conventional SLNR
algorithm. PSLNR is proposed in the present disclosure, which is a
signal to leakage and noise ratio based on a priority. PSLNR is
defined as follows:
.times..times..times..times..alpha..times..noteq..times..times..times..ti-
mes..times..alpha..times..noteq..times..times..times..times.
##EQU00001##
where H.sub.ii represents a channel matrix from the i-th secondary
device to a secondary device as the receiving terminal
communicating with the i-th secondary device, F.sub.i represents a
precoding matrix of the i-th secondary device, and
F.sub.i=F.sub.i.sup.(1)F.sub.i.sup.(2), X.sub.i represents data
transmitted by the i-th secondary device, .alpha..sub.i represents
an interference leakage weighting factor for the i-th secondary
device, H.sub.ir represents a channel matrix from the i-th
secondary device to an r-th other secondary device, n.sub.si
represents an additive noise for the i-th secondary device, and
I.sub.N represents a power of a noise for the i-th secondary
device.
A numerator part of the above equation (2) represents a power of a
useful signal of the i-th secondary device, and a first term of a
denominator part represents a sum of powers leaked from the i-th
secondary device to other (k-1) secondary devices, that is,
interference from the i-th secondary device to other secondary
devices, and a second term of the denominator part represents a
power of the noise.
In this case, a process of solving an optimization problem of the
second-stage precoding matrix F.sub.i.sup.(2) of the i-th secondary
device may be represented as follows:
.times..times..ltoreq..times. ##EQU00002##
where P.sub.i is a transmission power of the i-th secondary device.
The above equation (3) shows that, the second-stage precoding
matrix F.sub.i.sup.(2) is obtained by solving a precoding matrix
which can maximize a value of PSLNR. The second-stage precoding
matrix F.sub.i.sup.(2) obtained by solving may be represented as
follows:
.PHI..function..alpha..times..noteq..times..times..times..times..times..t-
imes..times..times..times. ##EQU00003##
where .PHI.[A,B] represents a characteristic factor corresponding
to a maximum characteristic value of a matrix pencil composed of A
and B.
As can be seen from the above equation (4) that, the interference
leakage weighting factor .alpha. is introduced in calculation of
the second-stage precoding matrix, and .alpha. is determined based
on a priority of the secondary device. Hence, different priorities
of the secondary device are taken into consideration in the
second-stage precoding according to the present disclosure, in this
way, a purpose of guaranteeing different QoS for secondary devices
having different priorities can be achieved.
Next, in step S730, for an i-th secondary device as a receiving
terminal, a demodulation and weighting matrix w.sub.si is
determined using MMSE criterion, as shown in the following equation
(5):
.alpha..times..noteq..times..times..times..times..times..times.
##EQU00004##
Where F.sub.i=F.sub.i.sup.(1)F.sub.i.sup.(2).
FIG. 8 shows a structural block diagram of a secondary device
according to the present disclosure. As shown in FIG. 8, the
secondary device 800 includes a determining unit 810, a first
precoding unit 820, a second procoding unit 830, a demodulating
unit 840, a generating unit 850, an interference channel
information determining unit 860 and a communication unit 870. It
is noted that, the interference channel information determining
unit 860 may be optional, for example, in embodiments shown in
FIGS. 4A and 5A, the secondary device 800 may not include the
interference channel information determining unit 860.
The determining unit 810 is configured to determine one or more of
position information, a priority, payment information, device
capability information of the secondary device 800, to report
related information to a SC. The first precoding unit 820 is
configured to perform first-stage SP precoding as described above
using interference channel information from the secondary device
800 to the interfered primary device. The second precoding unit 830
is configured to perform second-stage precoding using interference
channel information from the secondary device 800 to other
interfered secondary device and an interference leakage weighting
factor. The demodulating unit 840 is configured to perform
demodulation using the interference channel information from the
secondary device 800 to the interfered primary device and the
interference channel information from the secondary device 800 to
other interfered secondary device and the interference leakage
weighting factor according to MME criterion. The generating unit
850 is configured to generate information indicating whether the
secondary device 800 can perform first-stage SP precoding, to
report to the SC. In the embodiments of FIGS. 4B to 4C and FIGS. 5B
to 5C, the interference channel information determining unit 860 of
the secondary device 800 may be configured to determine
interference channel information from the secondary device 800 to
the interfered primary device or interference channel information
from the secondary device 800 to other interfered secondary device.
Further, the communication unit 870 is configured to
transmit/receive a signal between the secondary device 800 and the
SC or between the secondary device 800 and other secondary
device.
FIG. 9 shows a block diagram of a spectrum coordinator (SC)
according to the present disclosure. As show in FIG. 9, a SC 900
includes an interference leakage weighting factor determining unit
910, a transmission power determining unit 920, a storage unit 930,
an interference channel information determining unit 940 and a
communication unit 950. It should be noted that, the interference
channel information determining unit 940 may be optional, for
example, in the embodiments as shown in FIGS. 4B to 4C and FIGS. 5B
to 5C, the SC 900 may not include the interference channel
information determining unit 940.
The interference leakage weighting factor determining unit 910 is
configured to determine an interference leakage weighting factor
for a secondary device based on one or more of position
information, an operating power, a transmission power, a priority
and payment information of the secondary device. The transmission
power determining unit 920 is configured to determine a
transmission power for the secondary device based on whether the
secondary device can perform SP precoding. The storage unit 930 is
configured to store the position information, the operating
frequency, the transmission power, the priority, the payment
information, device capability information and the like of the
secondary device, and may also store position information, an
operating frequency, device capability information and the like of
the primary device in a primary system. In the embodiments of FIGS.
4A and 5A, the interference channel information determining unit
940 may be configured to determine interference channel information
from the secondary device to the interfered primary device or other
interfered secondary device using an AGE database. The
communication unit 950 is configured to transmit/receive a signal
between the SC 900 and the secondary device or the primary
device.
The primary system discussed herein may be, for example, an
American Radar System (3550-3650 MHz) proposed by Federal
Communications Commission (FCC) or a television broadcasting
system. Additionally, the technology according to the present
disclosure may be applied in for example a LTE-U system on 5 GHZ
frequency band.
The specific embodiments of the present disclosure are described
above in conjunction with the drawings, and the following technical
effects can be achieved according to the technology of the present
disclosure.
The transmitting terminal adopts two-stage precoding, thereby
suppressing interference to the primary device on the same
frequency band and interference to other secondary device on the
same frequency band.
On the premise of guaranteeing QoS of the primary device, different
levels of QoS can be guaranteed for secondary devices having
different priorities. A secondary device having a higher priority
can obtain higher QoS than a secondary device having a lower
priority.
SP precoding is used to suppress interference from the secondary
device to the primary device. As a result, compared with the
conventional power control method, a limitation on the maximum
transmission power of the secondary device using SP precoding is
relaxed, and the transmission power may be increased by 26 dB at
most.
The present disclosure can be applied to not only a DSA system in
which the priorities of the secondary devices are different, but
also a DSA system in which priorities of the secondary devices are
the same. In a case where the present disclosure is applied to the
DSA system in which the priorities of the secondary devices are the
same, the interference leakage weighting factors for various
secondary devices are set to be equal values.
Based on a case that multiple networks such as a macro cell, a
small cell, a pico cell, a home base station, a D2D coexist in a
current mobile cellular network, a layered/hierarchical cellular
network becomes an application scenario of cognitive radio in the
5G mobile communication. Hence, the present disclosure in
conjunction with a feature development trend has a wide application
prospect.
It is noted that, the various devices or components described
herein are only logical and do not strictly correspond to physical
devices or components. For example, the functions of each of the
components described herein may be implemented by multiple physical
entities, or the functions of multiple components described herein
may be implemented by a single physical entity.
The series of processing performed by each device or component in
the above-described embodiment may be implemented by software,
hardware, or a combination of software and hardware. The programs
included in the software may be stored in advance in a storage
medium provided inside or outside each device or component. As an
example, during execution, the programs are written to a random
access memory (RAM) and executed by a processor (such as a
CPU).
FIG. 10 is a block diagram of an exemplary configuration of
computer hardware for executing the above-described series of
processing based on the programs.
In a computer 1000, a central processing unit (CPU) 1001, a read
only memory (ROM) 1002 and a random access memory (RAM) 1003 are
connected via a bus 1004.
An input/output interface 1005 is further connected to the bus
1004. The input/output interface 1005 is connected with the
following components: an input unit 1006 in a form of a keyboard, a
mouse, a microphone and the like; an output unit 1007 in a form of
a display, a speaker and the like; a storage unit 1008 in a form of
a hard disk, a non-volatile memory and the like; a communication
unit 1009 in a form of a network interface card (such as a local
area network (LAN) card, a modern and the like); and a driver 1010
for driving a removable medium 1011 such as a magnetic disk, an
optical disk, a magneto-optical disk or a semiconductor memory.
In a computer having the above-described structure, the CPU 1001
loads the programs stored in the storage unit 1008 to the RAM 1003
via the input/output interface 1005 and the bus 1004, and executes
the programs so as to perform the above-described series of
processing.
The programs to be executed by the computer (the CPU 1001) may be
recorded on the removable medium 1011 as a package medium in a form
of, for example, a magnetic disk (including a floppy disk), an
optical disk (including a compact disk-read only memory (CD-ROM)),
a digital versatile disk (DVD) and the like), a mango-optical disk
or a semiconductor memory. Alternatively, the programs to be
executed by the computer (the CPU 1001) may also be provided by a
wired or wireless transmission medium such as a local area network,
Internet or digital satellite broadcasting.
The programs may be loaded in the storage unit 1008 via the
input/output interface 1005 in a case that the removable medium
1011 is mounted in the driver 1010. In addition, the programs may
be received by the communication unit 1009 via a wired or wireless
transmission medium, and are installed in the storage unit 1008.
Alternatively, the programs may be installed in advance in the ROM
1002 or the storage unit 1008.
The programs to be executed by the computer may execute the
processing according to an order described in the specification, or
may be execute the processing in parallel or execute the processing
when necessary (such as when being called).
The embodiments and technical effects of the present disclosure
have been described in detail in conjunction with the accompanying
drawings as above, but the scope of the present disclosure is not
limited thereto. Those skilled in the art should understand that,
various modifications and variations can be made on the embodiments
discussed herein without departing from the principle and spirit of
the present disclosure, depending on design requirements and other
factors. The scope of the present disclosure is defined by the
appended claims or the equivalents thereof.
Furthermore, the present disclosure may also be configured as
follows.
A spectrum management device includes one or more processors
configured to: determine position information of each secondary
device in a secondary system comprising a plurality of secondary
devices; and determine a weighting factor for a specific secondary
device based on the position information, where the weighting
factor is used to adjust estimation of power leaked from the
specific secondary device to other secondary devices.
The one or more processors are further configured to: determine a
priority for each of the secondary devices; determine the number of
the priorities of all active secondary devices on the same
frequency band as the specific secondary device within a
predetermined range of the specific secondary device, and
preliminarily determine a value of the weighting factor based on
the number of the priorities; and adjust the preliminarily
determined value based on the number or a distribution density of
the active secondary devices on the same frequency band as the
specific secondary device which have the same priority as the
specific secondary device, to determine the weighting factor.
The weighting factor is determined to be smaller in a case where
the specific secondary device has a higher priority.
The one or more processors are further configured to preliminarily
determine the value of the weighting factor evenly within a range
from 0 to 1 based on the number of the priorities of all active
secondary devices on the same frequency band as the specific
secondary device.
The one or more processors are further configured to increase the
preliminarily determined value in a case where the number or the
distribution density of the active secondary devices on the same
frequency band as the specific secondary device which have the same
priority as the specific secondary device exceeds a predetermined
threshold.
The one or more processors are further configured to determine
payment information of the specific secondary device, and determine
the weighting factor for the specific secondary device based on the
payment information.
The one or more processors are further configured to: determine
whether the specific secondary device is capable of performing
first-stage precoding; and determine a transmission power for the
specific secondary device based on a result of the determination,
where a higher transmission power is determined for the specific
secondary device in a case where the specific secondary device is
capable of performing the first-stage precoding.
The one or more processors are further configured to: determine,
using a channel information database, a first interference channel
information from the specific secondary device to a specific
primary device in a primary system and a second interference
channel information from the specific secondary device to other
secondary devices, based on the position information and the
transmission power of the specific secondary device.
The one or more processors are further configured to: determine
position-related information and/or device capability information
of a specific primary device in a primary system, and
position-related information and/or device capability information
of other secondary devices, based on the position information and
the transmission power of the specific secondary device.
A secondary device in a secondary system includes one or more
processors configured to determine position information of the
secondary device, so that a spectrum management device determines a
weighting factor for the secondary device based on the position
information.
The one or more processors are further configured to perform
second-stage precoding in which the weighting factor determined by
the spectrum management device is used to adjust estimation of
power leaked from the secondary device to other secondary
devices.
The one or more processors are further configured to determine a
priority for the secondary device, so that the spectrum management
device determines the weighting factor based on the priority, and
the weighting factor is determined to be smaller in a case where
the secondary device has a higher priority.
The weighting factor is determined by the spectrum management
device based on the number of the priorities of all active
secondary devices on the same frequency band as the secondary
device within a predetermined range of the secondary device, and
the number or a distribution density of the secondary devices
having each of the priorities.
The one or more processors are further configured to: perform
first-stage precoding before performing the second-stage
precoding.
The one or more processors are further configured to generate
information indicating whether the secondary device is capable of
performing the first-stage precoding, so that the spectrum
management device determines a transmission power for the secondary
device based on the information, and the spectrum management device
determines a higher transmission power for the secondary device in
a case where the information indicates that the secondary device is
capable of performing the first-stage precoding.
The one or more processors are further configured to: perform the
first-stage precoding using a first interference channel
information from the secondary device to a specific primary device
in a primary system; and perform the second-stage precoding using a
second interference channel information from the secondary device
to other secondary devices in the secondary system.
The first interference channel information and the second
interference channel information are determined by the spectrum
management device using a channel information database based on the
position information and the transmission power of the secondary
device.
The one or more processors are further configured to: determine the
first interference channel information based on position-related
information and/or device capability information of the specific
primary device determined by the spectrum management device; and
determine the second interference channel information based on
position-related information and/or device capability information
of the other secondary devices determined by the spectrum
management device.
The one or more processors are further configured to: determine
device capability information of the specific primary device using
position-related information of the specific primary device
determined by the spectrum management device, to perform channel
measurement, so as to determine the first interference channel
information; and determine device capability information of the
other secondary devices using position-related information of the
other secondary devices determined by the spectrum management
device, to perform channel measurement, so as to determine the
second interference channel information.
The device capability information includes an antenna array type,
an antenna boresight azimuth angle, and an antenna boresight
elevation angle.
The position-related information of the specific primary device is
position information of a reference point, and the reference point
is a position within a coverage area of the primary system which is
closest to the secondary device.
The one or more processors are further configured to demodulate a
received signal using the weighting factor, the first interference
channel information and the second interference channel
information.
A method for suppressing interference in a communication system,
wherein the communication system includes a spectrum management
device, a primary system including multiple primary devices, and a
secondary system including multiple secondary devices. The method
includes: transmitting position information of each of the
secondary devices to the spectrum management device; determining,
by the spectrum management device, a weighting factor for a
specific secondary device based on the received position
information; and performing second-stage precoding, in which the
weighting factor is used to adjust estimation of power leaked from
the specific secondary device to other secondary devices.
The weighting factor has a value ranging from 0 to 1.
The method further includes: transmitting a priority of each of the
secondary devices to the spectrum management device; and
determining, by the spectrum management device, the weighting
factor for the specific secondary device based on the received
priorities, wherein the weighting factor is determined to be
smaller in a case where the specific secondary device has a higher
priority.
The method further includes: determining the number of the
priorities of all active secondary devices on the same frequency
band as the specific secondary device within a predetermined range
of the specific secondary device, and preliminarily determining a
value of the weighting factor based on the number of the
priorities; and adjusting the preliminarily determined value based
on the number or a distribution density of the active secondary
devices on the same frequency band as the specific secondary device
which have the same priority as the specific secondary device, to
determine the weighting factor.
The method further includes: performing first-stage precoding
before performing the second-stage precoding.
The method further includes: transmitting information indicating
whether the specific secondary device is capable of performing the
first-stage precoding to the spectrum management device; and
determining, by the spectrum management device, a transmission
power for the specific secondary device based on the information,
where a higher transmission power is determined for the specific
secondary device in a case where the information indicates that the
specific secondary device is capable of performing the first-stage
precoding.
The method further includes: determining, by the spectrum
management device using a channel information database, a first
interference channel information from the specific secondary device
to a specific primary device in the primary system and a second
interference channel information from the specific secondary device
to other secondary devices based on the position information and
the transmission power of the specific secondary device; and
transmitting, by the spectrum management device, the first
interference channel information and the second interference
channel information to the specific secondary device.
The method further includes: determining, by the spectrum
management device, position-related information and/or device
capability information of a specific primary device in the primary
system, and position information and/or device capability
information of other secondary devices, based on the position
information and the transmission power of the specific secondary
device, and transmitting the determined information to the specific
secondary device; determining, by the specific secondary device, a
first interference channel information from the specific secondary
device to the specific primary device based on the position
information and/or the device capability information of the
specific primary device, and determining, by the specific secondary
device, a second interference channel information from the specific
secondary device to the other secondary devices based on the
position information and/or the device capability information of
the other secondary devices.
The method further includes: determining, by the spectrum
management device, position-related information of a specific
primary device in the primary system and position-related
information of other secondary devices based on the position
information and the transmission power of the specific secondary
device, and transmitting the determined information to the specific
secondary device; and determining, by the specific secondary
device, device capability information of the specific primary
device based on the position-related information of the specific
primary device, to perform channel measurement, so as to determine
the first interference channel information; and determining, by the
specific secondary device, device capability information of the
other secondary devices based on the position-related information
of the other secondary devices, to perform channel measurement, so
as to determine the second interference channel information.
The method further includes demodulating, by the specific secondary
device, a received signal using the weighting factor, the first
interference channel information and the second interference
channel information.
* * * * *